A two-point scheme for optimal breast IMRT treatment planning

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• Breast and chest wall radiotherapy often faces challenges with breathing motion and skin dose.
• Current treatment planning methods may not fully optimize beam weights for these specific issues.

Purpose of the Study:

• To develop and evaluate an approach for determining optimal beam weights in intensity-modulated radiation therapy (IMRT) for breast/chest wall treatment plans.
• To decrease breathing effects and optimize skin dose (maximize if in target, minimize if not).

Main Methods:

• A novel method using two points in the target to calculate optimal beam weights was proposed.
• Retrospective planning of six breast and five chest wall cases using the Eclipse treatment planning system.
• Comparison of optimal plans against 3D CRT and non-optimal IMRT plans, including experimental verification with a MapCHECK device on a motion simulation table.

Main Results:

• Optimal IMRT plans showed comparable or superior dose uniformity, homogeneity, and conformity to the target compared to 3D CRT plans, particularly at beam junctions involving supraclavicular nodes.
• Optimal plans demonstrated improved dose distributions at shallow depths, effectively managing skin dose and breathing effects compared to non-optimal plans.
• Experimental validation confirmed the benefits of the optimal planning approach in mimicking breathing motion.

Conclusions:

• The proposed approach for optimal beam weight determination in IMRT for breast/chest wall treatments offers significant advantages in dose distribution and motion management.
• This method enhances treatment plan quality, especially in complex cases involving critical structures and patient motion.
• The findings suggest a potential improvement in radiotherapy efficacy and safety for breast and chest wall cancer patients.